The game is set in the Cartoon Wasteland, a pen-and-paper stylised world, created in the game's narrative by the sorcerer Yen Sid, as a place for "forgotten things", namely disused or obscure Disney characters. It is physically inspired by Disneyland, and appears as an intricate model in Yen Sid's workshop. However, Mickey Mouse's tampering with Yen Sid's magic paint brush and paint thinner causes mass damage to the model, creating a post-apocalyptic landscape. The land is tormented by the evil Blot, a monstrous being loosely based on the Phantom Blot, an antagonist to Mickey in the comic strips created by Floyd Gottfredson. There are also the Beetleworx, mismatched audio-animatronics designed by the Mad Doctor.
Mickey Mouse, out of curiosity, enters Yen Sid's workshop through a mirror in his house and discovers the model of a land (which resembles Disneyland) that Yen Sid created for forgotten Toons and the tool used to create it, the magic paintbrush. Fiddling with the brush and some paint to make a self-portrait, Mickey accidentally creates the Blot. Panicking, Mickey quickly tries to erase the Blot by throwing paint thinner onto it, but spills more paint on the model in the process. Upon seeing Yen Sid approaching, Mickey quickly tries to clean up the mess, but in his haste, spills thinner onto the paint spillage as he flees back to his house, while the Blot, having survived Mickey's attempt to destroy it, enters through a portal created by the paint/thinner mixture and takes control of the ruined world from its first resident, Oswald the Lucky Rabbit.
Epic Mickey recieved average to positive reviews, mainly criticizing it's camera, lack of voice acting and control issues.